The objective of the proposed project is to develop a real time high frequency ultrasound imaging system with a frame rate at a minimum of 180 Hz for cardiac applications in small animals. Ultrasound imaging is a well established technology for cardiac imaging on humans. For cardiac imaging in small animals whose hearts beat at a rate higher than 400 beats/minute, the spatial and temporal resolutions of current clinical ultrasonic scanners are far from ideal and simply inadequate for such applications. Furthermore currently there are no commercial high frequency ultrasonic scanners developed for small animal imaging and eye imaging in humans that are capable of a frame rate higher than 30 Hz over a large field of view. Under the support of this grant a device which a mechanical sector scanner with a single element transducer capable of imaging the heart of a small animal at a frequency from 30 to 50 MHz at a frame rate at a minimum of 130 Hz has been designed, fabricated, and tested. Initial experiments performed on mice and zebrafish hearts. In the next grant period, the performance of the scanner will be further improved by increasing the frequency and frame rate and implementing coded excitation to increase the depth of penetration. Miniature light weight annular arrays which allow dynamic focusing will be developed to replace single element transducers for improved spatial resolution taking advantage of an annular array based digital imaging system being developed at the USC Transducer Resource. The servo-motor based mechanical probe will be developed in collaboration with Capistrano Lab. Potential applications of this device in quantitative measurements of cardiac anatomy and physiological functions in mice and zebrafish will be explored in collaborations with investigators from USC Children's Hospital and Medical School. PUBLIC HEALTH RELEVANCE: Project Narrative Small animals, including mice, rats, zebrafish, etc., have emerged as ideal models for the study of human diseases and drug development. Therefore, as the demand for the studies of small animals increases, so does the need for methods to accurately monitor physiological and functional activities on a small scale. The high frequency ultrasonic system will offer a multitude of opportunities for biomedical research.